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How to Decrease Spam in LISTSERV

Anti-Spam: Why Set Your List to Send=Public,Confirm or Send=Private,Confirm

By adding the Confirm option, the sender will be required to confirm their message before it is posted to the list. This reduces the problem of spammers posting to your list by faking the return address.

What difference will your users experience?

When someone sends an email message to your list, LISTSERV will respond to the sender with the following message:

For security reasons, the ITS-LISTSERV list has been configured to request positive confirmation of messages posted to the list. You must now confirm that the enclosed message did originate from you. To do so, simply reply to the present message and type "OK" (without the quotes) in the text of your message, or click on the link below. If this does not work, or if the message did not originate from you, then contact the list owner for assistance.

The sender must either reply to the message with OK (as described above) or click on the link provided in the email.

If they choose to click on the link, LISTSERV will return:

Anti-Spam: Tips to Decrease Spam to the List

Send Keyword Settings:

Send = Private,Confirm<- Recommended default setting for non-moderated lists.
Only members of the list can send to the list.

Send =Public,Confirm

Anyone can send to the list.

Send = Public,Confirm,Non-Member
These options allow anyone to post to the list, but if the sender address is not subscribed to the list, the sender must confirm their message before it is posted to the list. List members do not need to confirm their messages.

Send = Editor,Hold,Confirm,All
All messages must be approved by the editor (moderator) before being posted to the list.

Send = Service,Confirm
Service = *uiowa.edu,*.uiowa.edu

Filter=also,*@list.uiowa.edu

Setting the above Send and Service keywords will limit the allowed senders to uiowa.edu addresses.
Setting Filter=also,*@list.uiowa.edu disallows messages sent with the fake email return addresses of other LISTSERV lists.
Details about the service keyword are available at:http://www.lsoft.com/manuals/15.5/listkeyw.html#kService

Additional Keyword Settings:

Confidential = Yes<- Recommended default setting for lists.
Setting the Confidential command to Yes, removes the name of the list from the public list-of-lists.

Subscription = xxxxxxxx,Confirm
The Confirm option requires the sender to confirm their subscription.

Moderated or Announce-Only lists. You also set your list as moderated or announce-only.

Anti-Spam: Tips to Decrease Spam to the List Owner

LISTSERV 15.5 provides the following enhancement: All messages sent to the LISTSERV-REQUEST, ALL-REQUEST or listname-REQUEST addresses will require confirmation from the sender before they will be passed on to the appropriate person(s).

There is not a confirmation for messages sent to the OWNER-listname address. That is a special administrative address used by LISTSERV to interact with list owners. By default all messages sent to OWNER-listname go to the list owner. We recommend you filter these messages based on the message subjects: Undelivered mail and error report. We will be creating an Outlook rule for Listserv error reports which will be available in the Office 365 Public Folders. See How to Filter Email Messages.

For edited lists, set Send = Editor,Hold,Confirm,All
This setting will require that all senders confirm that they actually sent the message before it is forwarded to you, the editor.

If you are tired of receiving the message below, we suggest you set a filter to remove them from your inbox. See How to Filter Email Messages.

The enclosed message, found in the listname mailbox and shown under

the spool ID 26241576 in the system log, has been identified as a

possible delivery error notice for the following reason: "Sender:",

"From:" or "Reply-To: "field pointing to the list has been found in mail body."